DALLAS (CBSDFW.COM) - In just the past week, there have been two high-profile North Texas cases — an alleged sexual assault and an alleged child abduction — in which the victim and the suspect used Kik to communicate. Kik is a free instant messenger app that’s popular among teens and pre-teens.

Staff members at the Boys & Girls Club of East Dallas talked to members Thursday about the potential dangers in using the app. “We want to believe that the world is safe, but it is really not,” said Cherri Rowe with the Boys & Girls Club. “We tell them to put their safety first.”

Ruby Contreras of North Richland Hills told investigators that she was kidnapped by a man whom she met on Kik. The 14-year-old was missing for a week before the North Texas teenager was found in Mexico with 26-year-old Stephan Cox. Cox was arrested on a kidnapping charge.

Then, on Wednesday, a middle school teacher in the Cedar Hill Independent School District was arrested for allegedly having sexual relationships with two students. According to police records, teacher Marlena Mints exchanged messages with one of the students using Kik.